The present invention relates to equipment for the manufacture of composite filters.
Conventionally, the harmful effects of inhaling cigarette smoke are reduced by tipping cigarettes with composite filters, that is to say with filters obtainable by pairing together two or more filter plugs made of material having different filtration characteristics.
In the case of composite filters incorporating two filter plugs, for example, these are prepared employing machines in which first and second plugs dispensed from separate reservoirs are transferred along a direction transverse to their longitudinal axes, by respective trains of fluted rollers, onto a common take-up roller with peripheral flutes each designed to accommodate two axially aligned plugs making up a single filter element.
These composite elements are then transferred by rotary transfer means to a garniture section and formed into a filter rod.
Passing singly and in succession through the garniture section, the filter elements advance in end-to-end contact along a direction parallel with their longitudinal axes and are wrapped in a strip of paper material to form a continuous filter rod that will be divided up subsequently into single composite filters by a rotary cutter operating at the outfeed end of the garniture section.
In equipment of this prior art type, as described and illustrated in U.S. Pat. No. 4,044,659 for example, the garniture section is set at right angles to the feed direction followed by the filter elements along the rotary transfer means and on the common take-up roller.
With the two portions of the composite filter production line aligned on directions extending transversely one to another, an architecture of this type betrays drawbacks in terms both of its inordinately large proportions, particularly where systems may incorporate more than one line, and of the difficulty experienced by a single operator in supervising the various steps of the process.
The prior art also embraces production lines in which the garniture section extends substantially in alignment with the feed direction followed by the filter elements along the transfer means aforementioned.
The rotary transfer means in such lines comprise a first frustoconical roller by which the filters are received from the common take-up roller, turned through 90° about a vertical axis, and transferred to a further roller of which the function is to direct the composite filters onto the garniture section.
An arrangement of this type overcomes the problem of alignment between the rotary transfer means and the garniture section, thereby facilitating visual supervision of the line by an operator, but is cumbersome and lacking in speed.
The object of the present invention is to provide equipment of compact dimensions for assembling and feeding composite filters, from which the drawbacks described above will be absent.